Thursday 19 July 2012 16.41 EDT
First published on Thursday 19 July 2012 16.41 EDT

The last obstacle to Bradley Wiggins's victory in the Tour de France appeared to be removed as Vincenzo Nibali weakened on the slope of the Peyresourde yesterday but the events of the closing minutes of stage 17, a 143.5km circuit of the High Pyrénées, ensured that the nature of his victory will be discussed as long as there are people alive who still remember it – and probably, given cycling's love of myth and legend, for much longer.

As the riders crossed the Col de Menté, the Col des Ares, the Côte de Burs and the giant Port de Balès, the field was gradually reduced until only seven riders were left in the bunch.

The earlier part of the day had been enlivened by Thomas Voeckler's successful attempt to secure the king of the mountains jersey, which he managed by outsprinting Fredrik Kessiakoff, his young Swedish rival, to the top of the first three climbs, including the hors-catégorie Port de Balès, and by a crash in the feed zone involving Mark Cavendish and Richie Porte, two of Wiggins's Team Sky colleagues, who became entangled with a spectator's flag. But now the serious business began.

About a minute ahead, alone in the lead, lay Alejandro Valverde, the 32-year-old Spanish rider who returned at the start of the season from an 18-month doping suspension. Never a contender for overall victory in this year's Tour, Valverde was an irrelevance to Thursday's enthralling main narrative.

The seven-man bunch included Wiggins, his Sky mountain wingman Chris Froome and Nibali, whose own gregario di lusso, Ivan Basso, had already made his contribution.

Once a grand tour winner himself, Basso has also come back from a doping-related ban. Still a stylish figure on the bike but seemingly no longer able to switch on the turbochargers during a steep climb, he was the last of Nibali's Liquigas team-mates to fall back after shepherding his leader most of the way up to the summit of the Peyresourde, the final climb before the ascent to the 1,603m ski station at Peyragudes.

The other members of a diverse but distinguished final group were Tejay van Garderen of BMC Racing, who had seen his leader, Cadel Evans, humiliated once again; Thibaud Pinot of FDJ-BigMat, the youngest rider in the race and already a mountain stage winner; Jurgen van den Broeck of Lotto-Belisol, fourth in the overall classification; and Chris Horner of RadioShack, lying 13th. One by one Froome and Wiggins wore them down, with Nibali starting to drop back before they topped the Peyresourde.

"As they were fatiguing off I was feeling better," Wiggins said. "so it was actually getting slower the higher we got up. Once we went over the summit I knew Nibali was in trouble, and a few of the other guys. I had a little chat with Froomey on the descent and that was it."

But not quite. The two Sky men could be seen talking and listening to their radio earpieces and the outcome of their discussion was hard to interpret. Wiggins slipped to the front at the foot of the last climb but then Froome went ahead again. Both were spinning their gears at a high cadence and Froome was starting to make frequent glances back at his team-mate, pulling a few metres ahead while gesturing for Wiggins to hurry up and join him.

It was these signals that caused some to assume that Froome was demonstrating to Wiggins that he is the stronger man in the mountains, as some suspected him of doing before the finish at La Toussuire last Thursday, when he appeared to respond to radio instructions to slow down and allow his leader to catch up.

"It wasn't a beau geste," Laurent Jalabert, the retired French grand tour winner who now commentates for TV, said as last night's stage ended. "You don't do that between team-mates. I think it darkens the triumph of Wiggins."

A lot of people had come to that conclusion before the two protagonists were able to give their interpretations. Wiggins said that when he crossed the Peyresourde with Nibali in trouble, he knew for the first time that he had won the Tour – a seductive thought, and a dangerous one.

"We were talking about Nibali and we said, 'He's nailed, he's finished,'" he said. "I heard on the radio that we were alone, just the two of us. I just lost concentration and started thinking a lot of things. In that moment all the fight went out of the window, everything to do with performance."

They had talked about the time gap to Valverde. "Chris really wanted to win the stage today," Wiggins said, and it was clear that Froome had enough in the tank to have closed the gap to the Spaniard, which finished at 19sec, while narrowing his own 2min 5sec deficit to Wiggins in the overall standings. But the team's priority was clear and it was to ensure Wiggins's safe arrival.

"That was the plan for today, to work for Bradley and protect the yellow jersey," Froome said. "Everyone in the team has made sacrifices. Cavendish, he's made sacrifices every day, everyone in the team. That's cycling. It's our work."

Wiggins was quick to praise the work of his principal assistant. "Chris has the talent and in the years to come he'll have all the pressure of the press and so on," he said.

"Mentally he's very strong and I'm sure that he'll win the Tour one day."

But not this one, which has Wiggins's name on it. "Obviously we've got the time trial to come," the yellow jersey said, referring to Saturday's penultimate stage: a 53.5km race against the clock from Bonneval to Chartres, which follows tomorrow's undemanding 222.5km transition stage from Blagnac to Brive, and in which he will mount the final defence of his two-minute lead. "But that's very much our domain," he concluded. "You'd put your house on me not losing that sort of time."